AIM: To evaluate serum concentrations of angiogenesis-related cytokines in proliferative diabetic retinopathy (PDR) before and after vitrectomy. METHODS: Serum samples were collected from 30 PDR patients with varying severity before and after vitrectomy. Serum concentrations of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), interleukin-8 (IL-8) and interferon-inducible protein-10 (IP-10) were determined by enzyme-linked immunosorbent assays (ELISA). RESULTS: Serum concentrations of VEGF, PEDF, IL-8 and IP-10 were significantly higher in PDR patients than that in controls, respectively (P<0.05). VEGF concentration decreased significantly in postoperative samples than that in preoperative samples (P<0.05). The concentrations of PEDF, IL-8 and IP-10 did not exhibit significant changes after vitrectomy. CONCLUSION: Elevated cytokines levels in serum may be diagnostically useful in PDR. Angiogenesis-related cytokines play important roles in the development of PDR, and would instruct the risk assessment of pathogenetic condition in PDR patients.